Since patches are used by being affixed to the surface of the skin, they might be exposed to sunlight outdoors depending on the application site. Because of this, in a patch containing a compound that is susceptible to decomposition by UV rays from the sun, there are the problems that a drug within a base decomposes and cannot exhibit its proper efficacy, its photodecomposition products might induce side effects, etc.
As a way of avoiding such effects of UV rays, adding a UV blocker to the base or the support of a patch is usually tried.
For example, an external preparation for percutaneous administration in which a UV absorber, etc. is added to a base in order to stabilize ketoprofen, which is unstable toward light (ref. Patent Publication 1), an anti-inflammatory external skin preparation to which titanium oxide is added in order to suppress photosensitivity to a nonsteroidal anti-inflammatory agent (ref. Patent Publication 2), an external skin preparation for preventing inflammation due to exposure to UV rays and the resulting skin reaction, etc. (Patent Publication 3), etc. are known. Furthermore, patches in which a UV absorber/blocker is added to or kneaded with a support of the patch (ref. Patent Publications 4 to 7), etc. have also been reported.
[Patent Publication 1]
JP, B, 5-8169
[Patent Publication 2]
JP, A, 9-169658
[Patent Publication 3]
JP, A, 2000-136122
[Patent Publication 4]
JP, A, 3-76285
[Patent Publication 5]
JP, UA, 5-30118
[Patent Publication 6]
JP, A, 10-265371
[Patent Publication 7]
WO 01/68061